Patients with suspected aseptic necrosis (AN) of the femoral heads (carrying a diagnosis of Sickle Cell anemia or Systemic Lupus erythematosus) with normal plain x-rays of their hips undergo MRI and multiplanar reformation (MPR) on the CT scanner to determine whether any of the newly developed techniques in radiology is more sensitive than radionuclide imaging in making the diagnosis of AN. All studies, including those in nuclear medicine, are performed within one week of each other. Since entry criteria into this protocol are strict, only 15 patients have been admitted to it and the number of patients is too small at present to make an assessment regarding the efficacy of one technique over the other. The study also will provide a means to understand the natural history of the disease process, as we plan to repeat the radiographic studies at six months and one year after the initial examinations.